HEREDITY AND VARIATIONS - Jamb Biology Past Questions and Answers

Question 16:

• JAMB 1986

Which of the following is an example of discontinuous variation?

A. Skin colouration
B. Left handedness
C. Body weight
D. Height

Question 17:

• JAMB 1987

A gene which expresses itself only in the homozygous condition is

A. A mutant
B. Dominant
C. Recessive
D. Lethal

Question 18:

• JAMB 1987

An example of monohybride inheritance in man is

A. Astigmatism
B. Cretinism
C. Hyperthyroidism
D. Albinism

Question 19:

• JAMB 1987

If a plant homozygous for round and yellow (RR : YY), is crossed with a wrinkle green type (rr : yy) all of the resulting seeds will be

A. Blue and wrinkled
B. Round and yellow
C. Wrinkled and yellow
D. Round and greenish yellow

Question 20:

• JAMB 1987

The ratio of carriers to sicklers in the F₁ generation derived from a parental cross of two carriers of haemoglobin S gene is

A. 3 : 1
B. 1 : 3
C. 2 : 1
D. 1 : 2